Edwyn Frey is the eldest son of Ser Ryman Frey and the grandson of Ser Stevron Frey. At the start of the novels he is third in line to inherit the Twins. He is not a man of the sword, and there is no mention of him participting in the War of the Five Kings, however he is present at the siege of Riverrun.
A Storm of SwordsEdit
Edwyn accompanies his father and brothers out to greet Robb Stark and Catelyn Tully when they arrive for the wedding of Lord Edmure Tully and Roslin Frey. He acts courteously towards the nobles, offering them rooms within the castle, although he tells Robb that his troops must make use of three large banquet tents outside.
During the wedding he rejects Dacey Mormont's request of a dance fairly aggressively. Catelyn tries to grab hold of his arm and she feels the presence of armour underneath. She then slaps Edwyn and breaks his lip.
A Feast for CrowsEdit
Edwyn is present at the Siege of Riverrun, due to the fact that his father is leading the contingent of House Frey. He attends the war council of Ser Jaime Lannister, at which he gets into cross words with Lord Clement Piper. He is put in charge of the Frey contingent after his father is dismissed by Jaime.
Shortly after this he finds out that his father was murdered on his way back to the Twins. He suspects his brother, Black Walder Frey, who is currently at Seagard, but the actual culprits were the Brotherhood Without Banners. His father's death makes him next in line to become lord of the crossing upon the death of Lord Walder Frey.